import numpy as np
# 生成x1 x2的一维数组，范围[-4, 4]，步长1
x1 = np.arange(-4, 5, 1)
x2 = np.arange(-4, 5, 1)
# 生成网格
xx1, xx2 = np.meshgrid(x1, x2)
print(xx1)
print('=======')
print(xx2)


